OPTIONS

All these options obviously only make sense if enforced by the server side.
They have been implemented to resemble the git-daemon(1) options as
closely as possible.

--base-path <path>

Prepend path to requested CVSROOT

--strict-paths

Don’t allow recursing into subdirectories

--export-all

Don’t check for gitcvs.enabled in config. You also have to specify a list
of allowed directories (see below) if you want to use this option.

-V

--version

Print version information and exit

-h

-H

--help

Print usage information and exit

<directory>

You can specify a list of allowed directories. If no directories
are given, all are allowed. This is an additional restriction, gitcvs
access still needs to be enabled by the gitcvs.enabled config option
unless --export-all was given, too.

DESCRIPTION

This application is a CVS emulation layer for Git.

It is highly functional. However, not all methods are implemented,
and for those methods that are implemented,
not all switches are implemented.

Testing has been done using both the CLI CVS client, and the Eclipse CVS
plugin. Most functionality works fine with both of these clients.

LIMITATIONS

CVS clients cannot tag, branch or perform Git merges.

git-cvsserver maps Git branches to CVS modules. This is very different
from what most CVS users would expect since in CVS modules usually represent
one or more directories.

INSTALLATION

If you are going to offer CVS access via pserver, add a line in
/etc/inetd.conf like

cvspserver stream tcp nowait nobody git-cvsserver pserver

Note: Some inetd servers let you specify the name of the executable
independently of the value of argv[0] (i.e. the name the program assumes
it was executed with). In this case the correct line in /etc/inetd.conf
looks like

Only anonymous access is provided by pserve by default. To commit you
will have to create pserver accounts, simply add a gitcvs.authdb
setting in the config file of the repositories you want the cvsserver
to allow writes to, for example:

[gitcvs]
authdb = /etc/cvsserver/passwd

The format of these files is username followed by the encrypted password,
for example:

myuser:$1Oyx5r9mdGZ2
myuser:$1$BA)@$vbnMJMDym7tA32AamXrm./

You can use the htpasswd facility that comes with Apache to make these
files, but Apache’s MD5 crypt method differs from the one used by most C
library’s crypt() function, so don’t use the -m option.

Alternatively you can produce the password with perl’s crypt() operator:

This has the advantage that it will be saved in your CVS/Root files and
you don’t need to worry about always setting the correct environment
variable. SSH users restricted to git-shell don’t need to override the default
with CVS_SERVER (and shouldn’t) as git-shell understands cvs to mean
git-cvsserver and pretends that the other end runs the real cvs better.

For each repo that you want accessible from CVS you need to edit config in
the repo and add the following section.

[gitcvs]
enabled=1
# optional for debugging
logFile=/path/to/logfile

Note: you need to ensure each user that is going to invoke git-cvsserver has
write access to the log file and to the database (see
Database Backend. If you want to offer write access over
SSH, the users of course also need write access to the Git repository itself.

You also need to ensure that each repository is "bare" (without a Git index
file) for cvs commit to work. See gitcvs-migration(7).

All configuration variables can also be overridden for a specific method of
access. Valid method names are "ext" (for SSH access) and "pserver". The
following example configuration would disable pserver access while still
allowing access over SSH.

[gitcvs]
enabled=0
[gitcvs "ext"]
enabled=1

If you didn’t specify the CVSROOT/CVS_SERVER directly in the checkout command,
automatically saving it in your CVS/Root files, then you need to set them
explicitly in your environment. CVSROOT should be set as per normal, but the
directory should point at the appropriate Git repo. As above, for SSH clients
not restricted to git-shell, CVS_SERVER should be set to git-cvsserver.

For SSH clients that will make commits, make sure their server-side
.ssh/environment files (or .bashrc, etc., according to their specific shell)
export appropriate values for GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL,
GIT_COMMITTER_NAME, and GIT_COMMITTER_EMAIL. For SSH clients whose login
shell is bash, .bashrc may be a reasonable alternative.

Clients should now be able to check out the project. Use the CVS module
name to indicate what Git head you want to check out. This also sets the
name of your newly checked-out directory, unless you tell it otherwise with
-d <dir_name>. For example, this checks out master branch to the
project-master directory:

cvs co -d project-master master

Database Backend

git-cvsserver uses one database per Git head (i.e. CVS module) to
store information about the repository to maintain consistent
CVS revision numbers. The database needs to be
updated (i.e. written to) after every commit.

If the commit is done directly by using git (as opposed to
using git-cvsserver) the update will need to happen on the
next repository access by git-cvsserver, independent of
access method and requested operation.

That means that even if you offer only read access (e.g. by using
the pserver method), git-cvsserver should have write access to
the database to work reliably (otherwise you need to make sure
that the database is up-to-date any time git-cvsserver is executed).

By default it uses SQLite databases in the Git directory, named
gitcvs.<module_name>.sqlite. Note that the SQLite backend creates
temporary files in the same directory as the database file on
write so it might not be enough to grant the users using
git-cvsserver write access to the database file without granting
them write access to the directory, too.

The database can not be reliably regenerated in a
consistent form after the branch it is tracking has changed.
Example: For merged branches, git-cvsserver only tracks
one branch of development, and after a git merge an
incrementally updated database may track a different branch
than a database regenerated from scratch, causing inconsistent
CVS revision numbers. git-cvsserver has no way of knowing which
branch it would have picked if it had been run incrementally
pre-merge. So if you have to fully or partially (from old
backup) regenerate the database, you should be suspicious
of pre-existing CVS sandboxes.

You can configure the database backend with the following
configuration variables:

Configuring database backend

git-cvsserver uses the Perl DBI module. Please also read
its documentation if changing these variables, especially
about DBI->connect().

gitcvs.dbName

Database name. The exact meaning depends on the
selected database driver, for SQLite this is a filename.
Supports variable substitution (see below). May
not contain semicolons (;).
Default: %Ggitcvs.%m.sqlite

gitcvs.dbDriver

Used DBI driver. You can specify any available driver
for this here, but it might not work. cvsserver is tested
with DBD::SQLite, reported to work with
DBD::Pg, and reported not to work with DBD::mysql.
Please regard this as an experimental feature. May not
contain colons (:).
Default: SQLite

gitcvs.dbuser

Database user. Only useful if setting dbDriver, since
SQLite has no concept of database users. Supports variable
substitution (see below).

gitcvs.dbPass

Database password. Only useful if setting dbDriver, since
SQLite has no concept of database passwords.

Variable substitution

Git directory name, where all characters except for
alpha-numeric ones, ., and - are replaced with
_ (this should make it easier to use the directory
name in a filename if wanted)

%m

CVS module/Git head name

%a

access method (one of "ext" or "pserver")

%u

Name of the user running git-cvsserver.
If no name can be determined, the
numeric uid is used.

ENVIRONMENT

These variables obviate the need for command-line options in some
circumstances, allowing easier restricted usage through git-shell.

GIT_CVSSERVER_BASE_PATH takes the place of the argument to --base-path.

GIT_CVSSERVER_ROOT specifies a single-directory whitelist. The
repository must still be configured to allow access through
git-cvsserver, as described above.

When these environment variables are set, the corresponding
command-line arguments may not be used.

Eclipse CVS Client Notes

To get a checkout with the Eclipse CVS client:

Select "Create a new project → From CVS checkout"

Create a new location. See the notes below for details on how to choose the
right protocol.

Browse the modules available. It will give you a list of the heads in
the repository. You will not be able to browse the tree from there. Only
the heads.

Pick HEAD when it asks what branch/tag to check out. Untick the
"launch commit wizard" to avoid committing the .project file.

Protocol notes: If you are using anonymous access via pserver, just select that.
Those using SSH access should choose the ext protocol, and configure ext
access on the Preferences→Team→CVS→ExtConnection pane. Set CVS_SERVER to
"git cvsserver". Note that password support is not good when using ext,
you will definitely want to have SSH keys setup.

Alternatively, you can just use the non-standard extssh protocol that Eclipse
offer. In that case CVS_SERVER is ignored, and you will have to replace
the cvs utility on the server with git-cvsserver or manipulate your .bashrc
so that calling cvs effectively calls git-cvsserver.

Clients known to work

CVS 1.12.9 on Debian

CVS 1.11.17 on MacOSX (from Fink package)

Eclipse 3.0, 3.1.2 on MacOSX (see Eclipse CVS Client Notes)

TortoiseCVS

Operations supported

All the operations required for normal use are supported, including
checkout, diff, status, update, log, add, remove, commit.

Most CVS command arguments that read CVS tags or revision numbers
(typically -r) work, and also support any git refspec
(tag, branch, commit ID, etc).
However, CVS revision numbers for non-default branches are not well
emulated, and cvs log does not show tags or branches at
all. (Non-main-branch CVS revision numbers superficially resemble CVS
revision numbers, but they actually encode a git commit ID directly,
rather than represent the number of revisions since the branch point.)

Note that there are two ways to checkout a particular branch.
As described elsewhere on this page, the "module" parameter
of cvs checkout is interpreted as a branch name, and it becomes
the main branch. It remains the main branch for a given sandbox
even if you temporarily make another branch sticky with
cvs update -r. Alternatively, the -r argument can indicate
some other branch to actually checkout, even though the module
is still the "main" branch. Tradeoffs (as currently
implemented): Each new "module" creates a new database on disk with
a history for the given module, and after the database is created,
operations against that main branch are fast. Or alternatively,
-r doesn’t take any extra disk space, but may be significantly slower for
many operations, like cvs update.

If you want to refer to a git refspec that has characters that are
not allowed by CVS, you have two options. First, it may just work
to supply the git refspec directly to the appropriate CVS -r argument;
some CVS clients don’t seem to do much sanity checking of the argument.
Second, if that fails, you can use a special character escape mechanism
that only uses characters that are valid in CVS tags. A sequence
of 4 or 5 characters of the form (underscore ("_"), dash ("-"),
one or two characters, and dash ("-")) can encode various characters based
on the one or two letters: "s" for slash ("/"), "p" for
period ("."), "u" for underscore ("_"), or two hexadecimal digits
for any byte value at all (typically an ASCII number, or perhaps a part
of a UTF-8 encoded character).

Legacy monitoring operations are not supported (edit, watch and related).
Exports and tagging (tags and branches) are not supported at this stage.

CRLF Line Ending Conversions

By default the server leaves the -k mode blank for all files,
which causes the CVS client to treat them as a text files, subject
to end-of-line conversion on some platforms.

You can make the server use the end-of-line conversion attributes to
set the -k modes for files by setting the gitcvs.usecrlfattr
config variable. See gitattributes(5) for more information
about end-of-line conversion.

Alternatively, if gitcvs.usecrlfattr config is not enabled
or the attributes do not allow automatic detection for a filename, then
the server uses the gitcvs.allBinary config for the default setting.
If gitcvs.allBinary is set, then file not otherwise
specified will default to -kb mode. Otherwise the -k mode
is left blank. But if gitcvs.allBinary is set to "guess", then
the correct -k mode will be guessed based on the contents of
the file.

For best consistency with cvs, it is probably best to override the
defaults by setting gitcvs.usecrlfattr to true,
and gitcvs.allBinary to "guess".